Valve control mechanism for an internal combustion piston engine



W. RUDERT.

Feb. 18, 1969 VALVE CONTROL MECHANISM FOR AN INTERNAL COMBUSTION PISTON ENGINE Sheet Filed Aug. 17. 1967 INVENTOR WOLFGANG RUDERT BY P ATTORN w. RUDEIIZQT Feb. 18, I969 VALVE CONTROL MECHANISM FOR AN INTERNAL COMBUSTION PISTON ENGINE Sheet Filed Aug. 17, 1967 R O T mm W M R G N A m L 0 w 7 BY @M' ATTORNEY) United States Patent 3,428,032 VALVE CONTROL MECHANISM FOR INTERNAL COMBUSTION PISTON ENGINE Wolfgang Rudert, Grunbach Kreis, Waiblingen, Germany,

assignor to Daimler-Benz Aktiengesellschaft, Stuttgart- Unterturkheim, Germany Filed Aug. 17, 1967, Ser. No. 661,284 Claims priority, application Germany, Aug. 20, 1966,

D 50,900 US. Cl. 12s 90 12 Claims Int. Cl. F011 N26, ]/18 ABSTRACT OF THE DISCLOSURE The invention relates to a valve control mechanism for an internal combustion piston engine having two intake valves and two exhaust valves in each cylinder head, respectively, two identical valves being positioned in a plane parallel to the axes of the valve rockers and being driven by way of a rocker pair of two rocker arms connected with each other by a single web, and the forked arm provided therebetween, with actuation thereof being provided by means of one individual push rod for the pair of rocker arms and for the forked rocker, respectively.

It is the objective of the invention to accommodate such a valve control mechanism in as space-saving a manner as possible. This is accomplished by fashioning the connection of the rocker arm pair of two parallel webs and positioning the webs approximately in opposition to each other on either side of the axis of rotation of the rocker arms; and furthermore by mounting the pair of rockers and the forked rocker arm on axles, the center-to-center spacing of which is smaller than the sum of the radius of the hub of the pair of rockers and the radius of the hub of the forked rocker.

In a prior art valve control mechanism of the type mentioned above, the rockers of the rocker pair connected with each other by a single web, and the worked rocker arm are pivotable by means of pivot pins mounted in bearings which are offset with respect to each other by a relatively large horizontal distance, and are provided on a common bearing block. The valve control mechanism of this invention, in contradistinction thereto, provides an arrangement of elements which results in a substantially more compact construction. Furthermore, the disadvantage of use of a single web to connect the arms of a rocker arm pair in which web forces and moments are introduced asymmetrically to the axis of rotation of the pair of rockers, entailing the danger of an interlinking of the bearings, is avoided in the construction provided by the invention.

According to the invention, an axial guidance of the forked rocker arm can be achieved by having sections of the inner front faces of the hubs of the rocker pair contact the front faces of the hub of the forked rocker arm. In addition, a particularly simple and rigid arrangement of this valve control mechanism results, in accordance with the invention, from fastening the axles of the rockers directly to upwardly extended side walls of the cylinder head.

ICC

It is an object of the present invention to provide a valve control mechanism for an internal combustion engine which eliminates or otherwise avoids the disadvantages inherent in known devices of a similar type.

It is another object of the present invention to provide a valve control mechanism of the type described which is extremely compact and a rigid structural arrangement.

It is a further object of the present invention to provide a valve control mechanism of the type described wherein forces and asymmetrical forces are eliminated in a simple manner.

It is still another object of the present invention to provide a valve control mechanism of the type described wherein the structural arrangement inherently produces an axial guidance of the rocker arms.

These and other objects, features and advantages of the present invention will become more apparent from the following detailed description, when taken with the accompanying drawings, which illustrate two embodiments of the invention, and wherein:

FIGURE 1 shows a top plan view of a valve control mechanism with a valve rocker pair provided for actuation of the inlet valves;

FIGURE 2 is a section along line IIII of FIGURE 1;

FIGURE 3 is a top View of a valve control mechanism with a valve rocker pair for the outlet valves; and

FIGURE 4 is a section along line IVIV of FIG- URE 3.

Looking now to the drawings wherein similar reference numerals are employed for like components, throughout the various views, and particularly t the embodiment illustrated in FIGURES 1 and 2, a forked rocker arm 11 is pivotally mounted on an axle 12, this forked rocker arm operating the two exhaust valves 13 and 14. The inlet valves 15 and 16 are actuated by two rocker arms 17 and 18 which are combined, by webs 19 and 20, into a rocker arm pair pivotally mounted on an axle 21. The forked rocker 11 is actuated by a push rod 22, the rocker arm pair 17/ 18 is actuated by a push rod 23.

Reference numerals 24 and 25, respectively denote the impressed bearing bushings of the forked rocker 11 and the rocker arm pair 17/18, respectively. Valve spring retains 26 are attached to each of the valves 13 to 16 as abutments for the valve springs 43 thereof. Setscrews 27 at each rocker arm serve, together with nuts 28, as means for adjusting the valve play.

The rocker axles 12 and 21 are constructed as thickwalled tubular members provided at each end with two parallel flattened sections 29. The flattened sections 29 serve as means for bringing the axles 12 and 21 into engagement with the upwardly extended side walls 30 of the cylinder head 31, or for the contact of the heads of setscrews 32 for the axles 12 and 21. The side walls 30, in this connection, serve simultaneously for the axial guidance of the rocker arm pair 17/18. In contradistinction to the conventional bearing blocks arranged on the bottom of the cylinder head, this manner of mounting, in addition to relieving the cylinder head bottom of its load, results in a particularly rigid construction.

The axle 21 of the rocker arm pair 17/18 is offset laterally and with respect to height as seen in FIGURE 2 relative to the axle 12 of the forked rocker 11. The center-to-center distance d of the axles 12 and 21 is smaller than the sum of the radius r of the hub 33 of the rocker arm pair 17/18 and the radius r of the hub 34 of the forked rocker 11. The length of the hub 34 of the forked rocker arm 11 corresponds to the spacing of the two rockers 17 and 18 of the rocker arm pair, so that sections 35 of the front faces of the hub 34 of the forked rocker 11 contact sections 36 of the inner front faces of the hubs 33 of the rocker arm pair 17/18. The

forked rocker arm 11 is thereby axially guided by the rocker arm pair 17/18.

The two parallel webs 19 and 20 of the rocker arm pair 17/18 are provided with a cross-sectional area of a double-trapezoidal configuration, with great height and rounded corners. These webs are arranged on both sides of the rocker axle 21, so that large moments of rotation can be transmitted from the actuated rocker arm 17, at the one arm portion 37 at which the push rod 23 engages, to the rocker arm 18 without occurrence of any mutual twisting of the two rocker arms 17 and 18 with respect to each other and the deleterious consequences thereof.

FIGURES 3 and 4 show a similar arrangement of a valve control mechanism. The outlet valves 13 and 14, contrary to the embodiment of FIGURES 1 and 2, are actuated by a rocker pair 38/39, and the outlet valves and 16 are actuated by a forked rocker arm 40. The webs 41 and 42 between the rockers 38 and 39 have a trapezoidal cross-sectional area.

The rocker arm pair according to this invention can be manufactured in various ways. For example, an optimum configuration providing a most efficient utilization of material can be accomplished by producing the rocker arm pair in the shape of a cast body. A particularly advantageous manufacturing results by butt-welding the webs between two identical, drop-forged rocker arms. Also a tube, welded into the construction, of sufficient width and strength, and provided with two opposed longitudinal openings, is suitable for the webs of the arrangement of this invention. A further possibility resides in producing the rocker arm pair by a plug-in connection in the webs.

I have shown and described two embodiments in accordance with the present invention. It is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art and I, therefore, do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. A valve control mechanism for an internal combustion engine having at least a pair of inlet valves and a pair of outlet valves positioned in a cylinder head in respective substantially parallel planes, comprising: a rocker arm pair, including first and second pivotable rocker arms coupled to one of said pairs of valves with the pivot axis thereof substantially parallel to the plane of said valves, and bridging means rigidly interconnecting said first and second rocker arms; a forked rocker arm coupled to the other of said pairs of valves with the pivot axis thereof substantially parallel to the plane of said valves; a push rod coupled to each of said rocker arm pair and said forked rocker arm to effect actuation thereof; only two axles respectively mounting said forked rocker arm and said rocker arm pair about individual pivot axes thereof; said axle of said rocker arm pair being provided with hubs at the ends thereof and said axle of said forked rocker arm being provided with a single hub along the length thereof; the faces of the hubs of said rocker arm pair contacting the faces of the hub of said forked rocker arm to effect an axial locking thereof.

2. A valve control mechanism as defined in claim 1, wherein said bridging means includes first and second substantially parallel webs respectively positioned on opposite sides of the pivot axis of said rocker arm pair.

3. A valve control mechanism as defined in claim 2, wherein said push rods are equally laterally displaced from and on opposite sides of a plane passing midway between each pair of valves and transverse to said pivot axes.

4. A valve control mechanism as defined in claim 2, wherein said webs have a trapezoidal configuration in cross-section and are elongated in a direction substantially parallel with respect to each other in cross-section.

5. A valve control mechanism as defined in claim 2, wherein said axles are thick-walled tubular members having at least one flattened surface portion at each end in contact with said upwardly extending side walls of the cylinder head.

6. A valve control mechanism as defined in claim 1, wherein the center-to-center distance between said axles is smaller than the sum of the radius of the hubs of the rocker arm pair and the radius of the hub of the forked rocker arm.

7. A valve control mechanism as defined in claim 1, including only two axles respectively mounting said forked rocker arm and said rocker arm pair about individual pivot axes thereof; one of said axles being offset from the other axle in directions parallel to and transverse to the planes of said valves.

8. A valve control mechanism as defined in claim 1, wherein the length of said hub of said forked rocker arm is equal to the spacing of said first and second rocker arms of said rocker arm pair.

9. A valve control mechanism for an internal combustion engine having at least a pair of inlet valves and a pair of outlet valves positioned in a cylinder head in respective substantially parallel planes, comprising: a rocker arm pair, including first and second pivotable rocker arms coupled to one of said pairs of valves with the pivot axis thereof substantially parallel to the plane of said valves, and bridging means rigidly interconnecting said first and second rocker arms; a forked rocker arm coupled to the other of said pairs of valves with the pivot axis thereof substantially parallel to the plane of said valves; a push rod coupled to each of said rocker arm pair and said forked rocker arm to effect actuation thereof; only two axles respectively mounting said forked rocker arm and said rocker arm pair about individual pivot axes thereof; a plurality of upwardly extending sidewalls of said cylinder head, said axles engaging and being secured directly to said sidewalls.

10. A valve control mechanism as defined in claim 9, wherein one of said axles is offset from the other of said axles in directions parallel to and transverse to the planes of said valves.

11. A valve control mechanism as defined in claim 9, at least one of said forked rocker arm and said rocker arm pair having hub means with oppositely axially outwardly directed faces; said side walls having opposed axially inwardly directed faces engaging said hub means outwardly directed faces.

12. A valve control mechanism as defined in claim 11, wherein said hub means includes opposed inner faces and is rigidly secured to said rocker arm pair; said forked rocker arm having a single hub extending between said opposed faces; said single hub having oppositely directed outer faces axially engaging said opposed faces to effect an axial locking between said cylinder head, said rocker arm pair and said forked rocker arm.

References Cited UNITED STATES PATENTS 1,301,007 4/1919 Roof 123--90 X 2,303,324 12/1942 Brumby 12379 2,309,291 1/ 1943 Anderson et al 123-90 2,610,617 9/1952 Pielstick 12390 2,619,078 11/1952 Witzky et al 123-90 X FOREIGN PATENTS 659,539 3/1963 Canada.

AL LAWRENCE SMITH, Primary Examiner.

US. Cl. X.R. 

